Biological catalysts

 Enzymes: proteins inside cells that act as a catalyst.  Proteins = long amino acids chains that are folded into a specific shape. catalaseamylasetrypsin pepsin Enzymes s

 Catalyst : substance that speeds up the rate of a chemical reaction but is not itself changed by the reaction.

hydrogen peroxide For example; Hydrogen peroxide breaks down to water and oxygen 2H 2 O 2 2H 2 O O2O2 + water + oxygen (l) (g)

 In our livers, catalase is the specific enzyme that catalyses the breakdown of hydrogen peroxide into water and oxygen. Catalase Inside the Cell

Active site Enzyme Substrate Step 1: Enzyme binds to substrate.

Enzyme Product molecules (combined into something new or broken down into separate parts) Step 2: Substrate is changed into products.

Step 3: Enzyme releases substrate, ready to be re-used in another reaction.

 Sketch & label this enzyme reaction into your notes: Active site: place on the enzyme where the reaction occurs Substrate: molecules upon which enzymes act

In enzyme catalyzed reactions, enzymes A. become a part of the new products. B. are destroyed by the reactants. C. are not changed by the reaction. D. are changed by the reaction.

 Lock and Key Hypothesis: the active site specifically matches the shape of the substrate molecule. enzyme Enzymes work like locks and keys active site

 Enzyme function: Kres&NR=1 (2:02) Kres&NR=1

 At low temperatures, enzyme-controlled reactions go slowly.  At high temperatures, enzyme-controlled reactions go quickly until optimum temperature. Enzyme Reaction & Temperature

 Optimum temperature: The temperature at which the rate of reaction is fastest. Enzyme Reaction & Temperature

 Once optimum temperature is surpassed, the heat causes the enzyme to denature  Denature: The enzyme changes shape and the active site no longer matches the shape of the substrate molecule Enzyme Reaction & Temperature

 Enzymes prefer to work at an optimum pH. Outside of its pH range, the enzyme is denatured. Rate Of Reaction pH pepsinamylase Optimum pH Enzyme Reaction & pH

 Concentration of enzymes - the more enzymes, the faster the rate of reaction.

 Concentration of substrates - the more substrates, the faster the rate of reaction

What are some things that affect enzyme activity?